Sang-ho happens to peep through a hole in a worn wooden house ad watch a married couple as they engage in sex. Without knowing it, he gets excited and as a consequence, he starts to masturbate. At first, he feels quilty and ashamed but they young man grows more and more addicted to watching them in secret. Then seizing a moment when the husband is not home, Sang-ho goes downstairs. Imitating the husband's manner of foreplay even down to the sequence, the young man has sex with the wife.